Vehicle accessory for monitoring travel distance

ABSTRACT

A vehicle mileage tracking system including an input device mounted in the vehicle for receiving one of a first and second door unlock signals, and a vehicle tripmeter. The vehicle tripmeter is coupled to the input device and to a vehicle odometer sensor for accumulating a first accumulated travel distance during vehicle travel following receipt by the input device of the first door unlock signal, and for accumulating a second accumulated travel distance during vehicle travel following receipt by the input device of the second door unlock signal. The tripmeter does not accumulate the first accumulated travel distance during vehicle travel following receipt by the input device of the second door unlock signal. The vehicle mileage tracking system also preferably includes a display coupled to the vehicle tripmeter for selectively displaying the first and second accumulated travel distance. The input device is preferably a receiver for receiving a signal from a remote transmitter. The mileage tracking system may also include output means operatively coupled to the vehicle tripmeter for outputting accumulated vehicle mileage to a device remote from the vehicle. The output means may be a physical output port or may be a transmitter for transmitting the accumulated vehicle mileage via a wireless communication link.

BACKGROUND OF THE INVENTION

The present invention generally relates to a vehicle odometer. Moreparticularly, the present invention relates to an odometer/tripmeter fortracking business and personal mileage traveled by a vehicle.

Individuals who use their vehicle for both business and personal usetypically have to track their mileage for either business or personaltrips in order to be reimbursed or keep records for tax purposes. Insome cases, an individual may wish to track the total accumulatedmileage for their vehicle for each of several different purposes. Forexample, an individual may wish or need to keep track of the totalmileage traveled when using the vehicle for business or personal use soas to properly track business expenses associated with the vehicle overthe course of a year or other time period. Such tracking is important tobusiness owners in the United States, who may deduct from their taxesthe percentage of the expenses for a business owned or leased vehiclethat are related to the business use of the vehicle.

Currently, to keep track of mileage traveled for a particular trip, anindividual may either reset a tripmeter in the vehicle or note thecurrently displayed reading on the vehicle's tripmeter or odometer priorto commencing the trip. Subsequently, upon completing a trip, theindividual must read the tripmeter or odometer and take mental orphysical note of the reading prior to driving the vehicle any furtherdistance. Often, however, individuals forget to read the tripmeter orodometer upon commencing or completing the trip or forget to reset thetripmeter in the first place. Thus, current accessories provided in thevehicle for the purpose of tracking vehicle mileage are often of littlepractical assistance.

The above-noted problems are even more frustrating to those individualswho not only have to track the mileage for each business trip, but alsohave to add the mileage of each trip to a cumulative annual total.Presently there are no practical, commercially-available vehicleaccessories that allow an individual to keep track of cumulative traveldistance for a plurality of trips that are not sequentially traveledsuch as typically occurs when an individual intermittently drives theirvehicle for business and personal use. Although most vehicles are nowequipped with a tripmeter that tracks mileage separate from the odometerand that can be reset at the beginning of a trip, such tripmeters cannotbe stopped from accumulating mileage and then resume accumulating fromthe last recorded mileage figure. Existing accessories also do not allowfor such mileage information to be automtically recorded and transmittedto a computer or other device for tracking mileage for billing,reimbursement, and tax record keeping purposes.

Systems are described in the prior art that enable a driver to trackbusiness mileage separately from non-business mileage. See, for example,U.S. Pat. Nos. 5,579,242; 5,497,323; 5,267,159; 5,046,007; 4,875,167;4,755,832; 4,685,061; 4,593,263; and 4,547,781. However, such systemsstill require the driver to remember to manually inform the systemwhether the vehicle is being used for business or personal purposesprior to beginning travel. Also, many such systems include their ownhousings, multiple push-buttons, and other components such as printersand magnetic disk drives, that make these devices impractical and tooexpensive to implement in a vehicle.

SUMMARY OF THE INVENTION

Accordingly, it is an aspect of the present invention to provide avehicle tripmeter that solves the above problems by making it mucheasier for the driver to inform the tripmeter whether or not a trip willbe for business or personal purposes. More specifically, it is an aspectof the present invention to provide a vehicle tripmeter that enables adriver to inform the tripmeter that a trip is a business trip whileperforming a function the driver otherwise must perform to enter thevehicle, start the vehicle, or otherwise operate the vehicle. Inaddition, it is an aspect of the present invention to provide a vehicletripmeter for separately tracking business mileage that may be readilyintegrated into commercially available vehicle trip computers withoutrequiring significant hardware modification.

Additional features and advantages of the invention will be set forth inpart in the description which follows and in part will be apparent fromthe description, or may be learned by practice of the invention.

To achieve these and other aspects and advantages, the vehicle mileagetracking system of the present invention comprises an input devicemounted in the vehicle for receiving one of a first and second doorunlock signals, and a vehicle tripmeter coupled to the input device andto a vehicle odometer sensor for accumulating a first accumulated traveldistance during vehicle travel following receipt by the input device ofthe first door unlock signal, and for accumulating a second accumulatedtravel distance during vehicle travel following receipt by the inputdevice of the second door unlock signal, wherein the tripmeter does notaccumulate the first accumulated travel distance during vehicle travelfollowing receipt by the input device of the second door unlock signal.The vehicle mileage tracking system also preferably includes a displaycoupled to the vehicle tripmeter for selectively displaying the firstand second accumulated travel distance. The input device is preferably areceiver for receiving a signal from a remote transmitter.

The features and advantages of the invention may be realized andobtained by means of the instrumentalities and combinations particularlypointed out in the written description and claims hereof, as well as theappended drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are incorporated in, and constitute apart of, this specification illustrate several embodiments of theinvention and together with the description, serve to explain theobjects, advantages, and principles of the invention. In the drawings:

FIG. 1 is a cut-away perspective view of the interior of a vehicle thatincludes an overhead console incorporating a tripmeter constructed inaccordance with the present invention;

FIG. 2 is an electrical circuit diagram in block form of a tripmeterconstructed in accordance with a first embodiment of the presentinvention; and

FIG. 3 is an electrical circuit diagram in block form of a tripmeterconstructed in accordance with a second embodiment of the presentinvention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

As generally noted above, a mileage accumulation and display systemconstructed in accordance with the present invention includes an inputdevice mounted in the vehicle for receiving one of a first and seconddoor unlock signals, and a vehicle tripmeter coupled to the input deviceand to a vehicle odometer sensor for accumulating a first accumulatedtravel distance (e.g., business mileage) during vehicle travel followingreceipt by the input device of the first door unlock signal, and foraccumulating a second accumulated travel distance (e.g., non-businesspersonal mileage) during vehicle travel following receipt by the inputdevice of the second door unlock signal. The tripmeter does notaccumulate the first accumulated travel distance during vehicle travelfollowing receipt by the input device of the second door unlock signal.As described in more detail below with reference to FIGS. 1-3, the inputdevice includes a receiver circuit 15 and may also include a switchinterface circuit 17. The tripmeter may include a controller 20 and adisplay 25.

Switch interface circuit 17 may include a plurality of user-activatedpushbutton switches, such as switches 18 a-18 d in a trip computer on anoverhead console 38. Switch interface 17 may additionally oralternatively include the vehicle data entry system disclosed in U.S.Pat. No. 5,555,172 entitled “USER INTERFACE FOR CONTROLLING ACCESSORIESAND ENTERING DATA IN A VEHICLE,” and filed on Aug. 22, 1994, thedisclosure of which is incorporated by reference herein.

According to the most preferred embodiment of the present invention, theinput device includes a receiver circuit 15 that is coupled between anantenna 10 and controller 20. Receiver circuit 15 is preferablyconfigured to operate as a remote keyless entry (RKE) receiver and maybe responsive to either radio frequency (RF) or infrared (IR) signals.In this manner, receiver 15 may receive DOOR lock and unlock signalsfrom a key fob RKE transmitter 30 (FIG. 1). Unlike other portable RKEtransmitters, RKE transmitter 30 includes two different unlockpushbuttons 32 and 34 in addition to a lock pushbutton 36. A first oneof the unlock pushbuttons 32 is labeled “P” or “Personal” and the secondpushbutton is labeled “B” or “Business” to signify the purpose of a tripto be taken following entry into the vehicle. It will be appreciated bythose skilled in the art that other labels may be used so as todistinguish the two unlock pushbuttons and that more than two suchpushbuttons may be provided.

The vehicle tripmeter is coupled to a mileage sensor (or vehicleodometer) 40 through a discrete direct connection or through a vehiclebus 50 and vehicle bus interface circuit 52 (FIG. 2). While a separatereceiver or a separate controller coupled to receiver 15 may be used totransmit the door lock or door unlock commands to the vehicle's doorlocks 54, controller 20 of the tripmeter may also generate and transmitthese commands to door locks 54 either by discrete connection or bycommunication over vehicle bus 50.

In a most preferred embodiment, controller 20 is the microcontroller ofa vehicle trip computer. Such trip computers typically also include acompass sensor 56 and/or GPS receiver 58 as well as non-volatile memory60 that may be internal or external of controller 20. Conventional tripcomputers, such as those available from Johnson Controls Inc., generallyinclude a microcontroller, display, compass, user interface switches,and a vehicle bus interface coupled to the vehicle bus. Many of theconventional trip computers are mounted in an overhead console 38 orinside rearview mirror 39 of the vehicle, as are trainable transmitterssuch as the Homelink® trainable transmitter also available from JohnsonControls, Inc. Such trainable transmitters include an antenna, areceiver, and a transmitter coupled to a microcontroller. U.S. Pat. No.5,627,529 discloses a trainable transmitter that also functions as anRKE receiver. Thus, all of the physical components needed for thecarrying out the most preferred embodiments of the present invention arealready present in many overhead consoles and rearview mirrors. Further,trip computers typically provide a tripmeter function and include areset switch for resetting the tripmeter. In addition, many RKE key fobtransmitters include three manual switches with one for unlocking thedoors, another for locking the doors, and a third for other functionssuch as unlocking the trunk, panic alarm activation, or unlocking only aspecific door. Thus, to implement the preferred embodiments of thepresent invention, one would only need to reprogram the existingmicrocontroller(s) to respond to an activation of the third key fobbutton by unlocking the vehicle's doors and, at the same time, enablingaccumulation of either business or personal mileage.

In operation, a driver would simply press the unlock pushbutton 32labeled “P” if the trip the driver is about to embark upon is personalor press the unlock pushbutton labeled “B” if the trip is for businesspurposes. If unlock pushbutton B 34 is pressed, key fob transmitter 30transmits a first unlock signal that is received by receiver 15. Ifunlock pushbutton P 32 is pressed, key fob transmitter 30 transmits asecond unlock signal that is received by receiver 15. The second unlocksignal is distinguishable from the first unlock signal such thatcontroller 20 may respond differently to the receipt of these signals.In either event, the vehicle doors are unlocked.

Upon receiving the first unlock signal, controller 20 enables a businessmileage accumulator to begin or continue accumulation of mileage inresponse to signals from mileage sensor 40. This is accomplished byprogramming controller 20 to respond to the first unlock signal byadding to an accumulated value in memory 60 corresponding businessmileage in response to signals from mileage sensor 40. Controller 20could be programmed to reset the business mileage accumulator each timethe vehicle ignition is turned off. This would allow separate tripsegments to be stored for subsequent recordation in a travel log.

By providing sufficient memory, a plurality of such trip segments may bedate- and time-stamped and stored in memory for subsequent recall, atotal accumulated mileage and total accumulated business and/or personalmileage may also be stored in memory 60.

If the second unlock signal is received, controller 20 will not add tothe accumulated business mileage. Alternatively, the mileage could beaccumulated for that trip segment (i.e., from the time the vehicleignition is turned on until it is turned off), time- and date-stamped,and stored in memory with a designation that the mileage of that segmentwas for personal purposes.

In the event that neither the first nor the second unlock signal isreceived prior to detection that the vehicle ignition is turned on,controller 20 may, by default, enable the accumulation of businessmileage. Alternatively, controller 20 may be programmed to assume that anon-designated trip is personal as default. To ensure that the driverfailed to select “business” or “personal” by accident, controller 20 maycause a prompting message to be displayed on display 25 and/or generatean audio or other visual alarm.

If controller 20 is provided with a calendar function, controller 20 maystop accumulating business mileage associated with a specified timeperiod corresponding to a period in which taxes are calculated (e.g., acalendar year or quarter). Additionally, controller 20 may beginaccumulating business mileage data for the next tax or calendar year ina separate memory location. This allows the user to wait until aconvenient time to download the mileage data for a given tax period. Inaddition to the accumulated business mileage data for a given taxperiod, the vehicle odometer readings for the beginning of the tax yearand the end of the tax year may also be stored and downloaded. Thisallows a calculation of the percentage of miles that the vehicle wasdriven for business purposes during any given tax year.

In some cases, the driver of the vehicle is reimbursed for mileage on atrip-by-trip basis. For such drivers, the fact that the inventivetripmeter automatically stores time- and date-stamped mileage segmentsis particularly advantageous.

The mileage stored in memory 60 may be accessed using several differentmethods. A first method is simply to display the mileage on display 25when prompted to do so by the user. A “step” switch could be used tostep through the stored time and date-stamped mileage segments. If thevehicle is equipped with a large display such as those used in a vehiclenavigation system, the mileage data may be transferred to that displayover the vehicle bus.

A second method is to provide the vehicle or tripmeter with a dataoutput port 65 to which a portable electronic device, such as a laptopor pocket computer, may be coupled for downloading the data. The datamay be formatted for integration into any accounting or financingprogram. Such formatting would be particularly advantageous when theuser prepares his or her own taxes using a program such as TurboTax®from Intuit Inc., or the like.

A third method for accessing the data is to transmit the data using awireless communication link. The wireless communication link may be IRor RF. If the vehicle is equipped with a trainable transmitter 70, thetransmitter and antenna 72 of the transmitter may be used fortransmitting the mileage data. The transmitted RF mileage data may beinput into a computer 75 using several different setups. One setup wouldbe to transmit the data to a receiver 77 coupled to the AC power linesof the driver's home or office. The receiver would then modulate thereceived mileage data on the AC power such that it may be received by acommunication module coupled to the user's personal or laptop computer.Such a system would function similar to the X-10® system available fromX-10 Limited, of Hamilton, Bermuda.

The user's home or business computer may have an RF transceiver 77coupled directly to that computer 75 or indirectly through a local areanetwork (LAN), a wide area network (WAN), or through a global networksuch as the Internet. A particularly useful arrangement for a businesswould be to provide a transceiver near one or all entrance gates to theemployee parking lot(s) to transmit and receive signals from theemployees' vehicles as they travel through entrance gates. Thetransceiver could constantly transmit interrogation signals to which thetripmeters would respond by transmitting any mileage data back to thetransceiver. The mileage data could be coded with a vehicle or driveridentification code for purposes of reimbursing the employee. If thecomputer system connected to such a transceiver were programmedappropriately, the computer system could automatically generatereimbursement forms and e-mail them to the office computer of the driverof the vehicle so that the driver may enter any necessary informationinto the request and e-mail it back to the accounting department forissuance of a reimbursement check. Alternatively, if no additionalinformation is needed from the driver, the mileage data may betransferred directly to the accounting department for automatic ormanual printing of a reimbursement check.

In a similar manner, a user may place a transceiver in their home fortransmitting and receiving signals from the vehicle's memory. Thus, theuser's home computer may determine, for example, that it is December 31of a particular year and transmit an interrogation signal to the vehicleto cause the vehicle tripmeter to transmit back the mileage data forthat year.

The vehicle tripmeter of the present invention could also prompt thedriver to verify a selection. For example, the tripmeter could, afterreceiving one of the first or second door unlock signals, display amessage such as “Business,” “Business Trip Selected,” “Personal,” or“Personal Trip Selected.” The vehicle tripmeter thus prompts the driverto press a particular switch or sequence of switches to change thepurpose of the trip if the driver wishes to change his or her initialselection. The vehicle tripmeter could also be programmed to onlyactively seek verification upon certain circumstances. For example,since commuting to work generally does not qualify as a tax-deductiblebusiness trip, the vehicle may ask for verification that a selected trippurpose is in fact business when the vehicle determines that it islocated at the driver's home residence. The vehicle may make such adetermination based upon GPS data from GPS receiver 58, or from anactivation of the trainable transmitter to transmit a garage dooropening/closing signal just prior to ignition shut down in the priorignition cycle. Additionally, a home transceiver could issue a beaconsignal that is received by receiver 15 when the vehicle is in proximityto the driver's home. Conversely, when the driver selects a personaltrip when the tripmeter knows that the vehicle is at an offsite businesslocation or client location, it can prompt the driver to verify that thepurpose of the trip is in fact personal. The tripmeter may determinethat the vehicle is so located based upon GPS data and the past historyfor trips to locations having the same relative GPS position.

FIG. 3 shows a second embodiment of the present invention, which differsfrom the first embodiment in that a switch 80 is provided betweenmileage sensor 40 and controller 20. Switch 80 may be opened to preventcontroller 20 from receiving and accumulating the mileage clock signalfrom mileage sensor 40 as business trip mileage. Conversely, switch 80may be closed to allow controller 20 to receive and accumulate themileage clock signal from mileage sensor 40. In this manner, controller20 may be implemented using an existing microprocessor in a vehicle tripcomputer that does not need to be reprogrammed since such existingmicroprocessors merely count the clock pulses it receives. Further, ifreceiver 15 directly or indirectly transmits the unlock signals to doorlocks 54, controller 20 need not be coupled to receiver 15.

Switch 80 may be controlled by a switching signal transmitted fromreceiver 15 or optionally from controller 20. Switch 80 could also be amanual switch that is activated by the driver. Preferably, switch 80 maybe actuated by controller 20 since controller 20 could close or openswitch 80 in response to manual activation of one or more ofuser-actuated switches 17.

Although the inventive tripmeter has been described with respect to twotrip purposes (e.g., business and personal), the concepts described andclaimed herein may be used to identify more than two purposes. Forexample, separate mileage designations may be made for each businessaccount or for different businesses.

The above description is considered that of the preferred embodimentsonly. Modifications of the invention will occur to those skilled in theart and to those who make or use the invention. Therefore, it isunderstood that the embodiments shown in the drawings and describedabove are merely for illustrative purposes and not intended to limit thescope of the invention, which is defined by the following claims asinterpreted according to the principles of patent law, including thedoctrine of equivalents.

The invention claimed is:
 1. A vehicle mileage tracking system for usein a vehicle having a door lock for locking a door of the vehicle inresponse to a door lock signal and for unlocking the door in response tofirst and second door unlock signals, said system comprising: an inputdevice mounted in the vehicle for receiving first and second door unlocksignals; and a vehicle tripmeter coupled to said input device and to avehicle odometer sensor for accumulating a first accumulated traveldistance during vehicle travel following receipt by said input device ofsaid first door unlock signal, and for accumulating a second accumulatedtravel distance during vehicle travel following receipt by said inputdevice of said second door unlock signal, wherein said tripmeter doesnot accumulate said first accumulated travel distance during vehicletravel following receipt by said input device of said second door unlocksignal.
 2. The vehicle mileage tracking system as defined in claim 1 andfurther including a display coupled to said vehicle tripmeter forselectively displaying said first and second accumulated traveldistance.
 3. The vehicle mileage tracking system as defined in claim 1and further including a reset switch coupled to said vehicle tripmeterfor resetting said first or second accumulated travel distance to avalue of zero when said reset switch is activated.
 4. The vehiclemileage tracking system as defined in claim 1, wherein said input deviceis a receiver for receiving a signal from a remote transmitter.
 5. Thevehicle mileage tracking system as defined in claim 1 and furtherincluding output means coupled to said vehicle tripmeter for outputtingaccumulated vehicle mileage to a device remote from said vehicle.
 6. Thevehicle mileage tracking system as defined in claim 5, wherein saidoutput means includes a transmitter for transmitting the accumulatedvehicle mileage via a wireless communication link.
 7. The vehiclemileage tracking system as defined in claim 6, wherein said transmitteris an RF transmitter for transmitting an RF signal to a receiver coupledto the remote device.
 8. The vehicle mileage tracking system as definedin claim 1, wherein said vehicle tripmeter time- and date-stamps mileagetrip segments that are recorded between periods defined by the ignitionbeing turned on and off.
 9. The vehicle mileage tracking system asdefined in claim 8, wherein the mileage said vehicle tripmeter storesduring each trip segment is business mileage.
 10. The vehicle mileagetracking system as defined in claim 8, wherein said vehicle tripmeterfurther stores an indicator in association with each trip segmentwhether the trip segment was a business trip or a personal trip.
 11. Thevehicle mileage tracking system as defined in claim 1, wherein saidvehicle tripmeter totals one of the first and second travel distancestraveled during a specified period of time.
 12. The vehicle mileagetracking system as defined in claim 11, wherein each said specified timeperiod is a period during which taxes are calculated.
 13. The vehiclemileage tracking system as defined in claim 11, wherein each saidspecified time period is a calendar year.
 14. The vehicle mileagetracking system as defined in claim 11, wherein the mileage said controlcircuit totals during each specified time period is business mileage.15. The vehicle mileage tracking system as defined in claim 11, whereinthe mileage said control circuit totals during each specified timeperiod is personal mileage.
 16. A mileage display system for a vehiclefor use in a vehicle having a door lock for locking a door in responseto a door lock signal and for unlocking the door in response to firstand second door unlock signals, said system comprising: a portabletransmitter having a first manually actuated switch for causing saidtransmitter to transmit a first door unlock signal, a second manuallyactuated switch for causing said transmitter to transmit a second doorunlock signal, and a third manually actuated switch for causing saidtransmitter to transmit a door lock signal; a receiver mounted in thevehicle for receiving said first and second door unlock signals and saiddoor lock signal; and a vehicle tripmeter adapted to be coupled to avehicle odometer sensor, said vehicle tripmeter displays mileageaccumulated during vehicle travel following receipt by said receiver ofsaid second door unlock signal, wherein said tripmeter does notaccumulate mileage during vehicle travel following receipt by saidreceiver of said first door unlock signal.
 17. The mileage displaysystem as defined in claim 16 and further including a switching devicecoupled between said vehicle tripmeter and the odometer sensor forselectively disabling said vehicle tripmeter from incrementing thedisplayed accumulated travel when said receiver receives the first doorunlock signal and for selectively enabling said vehicle tripmeter toincrement the displayed accumulated travel when said receiver receivesthe second door unlock signal.
 18. The mileage display system as definedin claim 16, wherein said transmitter and said receiver are respectivelyconfigured to transmit and receive RF signals, and said first and seconddoor unlock signals and said door lock signal are RF signals.
 19. Amileage display system for a vehicle for use in a vehicle having a doorlock for locking a door in response to a door lock signal and forunlocking the door in response to first and second door unlock signals,said system comprising: an input device mounted in the vehicle forreceiving first and second door unlock signals; and a vehicle tripmetercoupled to said input device and to a vehicle odometer sensor fordisplaying mileage accumulated during vehicle travel following receiptby said input device of said second door unlock signal, wherein saidtripmeter does not accumulate mileage during vehicle travel followingreceipt by said input device of said first door unlock signal.
 20. Themileage display system as defined in claim 19 and further including aswitching device for selectively enabling/disabling said vehicletripmeter to/from incrementing the displayed accumulated travel.
 21. Themileage display system as defined in claim 19, wherein said input deviceis an RF receiver for receiving RF first and second door unlock signalsfrom a remote transmitter.
 22. The mileage display system as defined inclaim 19, wherein said input device is a user-actuated switch.
 23. Themileage display system as defined in claim 19, wherein the accumulatedmileage displayed by said vehicle tripmeter is mileage for one or morebusiness trips.
 24. A vehicle mileage accumulation and display systemfor use in a vehicle having a door lock for locking a door in responseto a door lock signal and for unlocking the door in response to firstand second door unlock signals, said system comprising: a receiver forreceiving a signal from a remote transmitter; a mileage accumulatorcoupled to said receiver for accumulating vehicle mileage received froma mileage sensor as the vehicle travels in response to a signal receivedby said receiver from the remote transmitter; and a display fordisplaying the vehicle mileage accumulated by said mileage accumulator.25. The mileage display system as defined in claim 24, wherein saidmileage accumulator includes an interface for coupling to an odometersensor of the vehicle to receive a vehicle travel distance signal fromwhich the vehicle mileage may be ascertained.
 26. The mileage displaysystem as defined in claim 25, wherein said mileage accumulator furtherincludes a switching device coupled to said interface for receiving andselectively transmitting the vehicle travel distance signal.
 27. Themileage display system as defined in claim 26, wherein said mileageaccumulator further includes: a memory device for storing cumulativetravel distance; and a processing circuit coupled to an output of saidswitching device and to said memory for calculating cumulative traveldistance in response to the vehicle travel distance signal selectivelytransmitted through said switching device and for storing the cumulativetravel distance in said memory.
 28. The mileage display system asdefined in claim 27, wherein said processing circuit is coupled to saidreceiver and controls said switching device to transmit the vehicletravel distance signal when the signal is received from said receiver.29. The mileage display system as defined in claim 24, wherein theaccumulated mileage displayed by said vehicle tripmeter is mileage forone or more business trips.
 30. A vehicle mileage accumulation anddisplay system for use in a vehicle having a door lock for locking adoor in response to a door lock signal and for unlocking the door inresponse to first and second door unlock signals, said systemcomprising: a portable transmitter having a first manually actuatedswitch for causing said transmitter to transmit a first door unlocksignal, a second manually actuated switch for causing said transmitterto transmit a second door unlock signal, and a third manually actuatedswitch for causing said transmitter to transmit a door lock signal; areceiver mounted in the vehicle for receiving said first and second doorunlock signals and said door lock signal; a vehicle tripmeter coupled tosaid receiver and adapted to be coupled to a vehicle odometer sensor,said vehicle tripmeter accumulates business travel distance duringvehicle travel following receipt by said receiver of said first doorunlock signal, and accumulates non-business accumulated travel distanceduring vehicle travel following receipt by said receiver of said seconddoor unlock signal, wherein said tripmeter does not accumulate saidbusiness travel distance during vehicle travel following receipt by saidreceiver of said second door unlock signal; and a display coupled tosaid vehicle tripmeter for selectively displaying said business andnon-business accumulated travel distance.